Ultrix (officially all-caps ULTRIX) is the brand name of Digital Equipment Corporation's (DEC) discontinued native Unix operating systems for the PDP-11, VAX, MicroVAX and .
DEC's Unix Engineering Group (UEG) was started by Bill Munson with Jerry Brenner and Fred Canter, both from DEC's Customer Service Engineering group, Bill Shannon (from Case Western Reserve University), and Armando Stettner (from Bell Labs). Other later members of UEG included Joel Magid, Bill Doll, and Jim Barclay recruited from DEC's marketing and product management groups.
Under Canter's direction, UEG released V7M, a modified version of Unix 7th Edition (q.v.).
In 1988 The New York Times reported that Ultrix was POSIX compliant.
According to Mike Humphries of Oracle Corporation, DEC's New Hampshire Unix group's real purpose was to persuade customers to stay with VMS, and only sell Unix to those that insisted on it. Shortly after IBM announced plans for a native UNIX product, Stettner and Bill Doll presented plans for DEC to make a native VAX Unix product available to its customers; DEC founder Ken Olsen agreed.
By 1985 most computer companies offered Unix as an alternative to their proprietary operating systems. DEC provided Ultrix on three platforms: PDP-11 minicomputers (where Ultrix was one of many available operating systems from DEC), VAX-based computers (where Ultrix was one of two primary OS choices) and the Ultrix-only DECstation workstations and DECsystem servers. Note that the DECstation and the later DECsystem products (as opposed to DEC's original DECsystem line) used MIPS processors and predate the much later DEC Alpha-based systems.
Notably, Ultrix implemented the inter-process communication (IPC) facilities found in System V (, Message passing, semaphores, and shared memory). While the converged Unix from the Unix wars (that spawned the Open Software Foundation or OSF), released late 1986, put BSD features into System V, DEC, as described in Stettner's original Ultrix plans, took the best from System V and added it to a BSD base.
Originally, on the VAX workstations, Ultrix-32 had a desktop environment called UWS, Ultrix Worksystem Software, which was based on X10 and the Ultrix Window Manager. Later, the widespread version 11 of the X Window System (X11) was added, using a window manager and widget toolkit named DECwindows (X User Interface), which was also used on VMS releases of the time. Eventually Ultrix also provided the Motif toolkit and Motif Window Manager.
Ultrix ran on multiprocessor systems from both the VAX and DECsystem families. Ultrix-32 supported SCSI disks and tapes and also proprietary Digital Storage Systems Interconnect and CI peripherals employing DEC's Mass Storage Control Protocol, although lacking the OpenVMS distributed lock manager it did not support concurrent access from multiple Ultrix systems. DEC also released a combination hardware and software product named Prestoserv which accelerated NFS file serving to allow better performance for diskless workstations to communicate to a file serving Ultrix host. The kernel supported symmetric multiprocessing while not being fully multithreaded based upon pre-Ultrix work by Armando Stettner and earlier work by George H. Goble at Purdue University. As such, there was liberal use of locking and some tasks could only be done by particular CPUs (e.g. the processing of ). This was not uncommon in other SMP implementations of that time (e.g. SunOS). Also, Ultrix was slow to support many then new or emerging Unix system capabilities found on competing Unix systems (e.g. it never supported shared libraries or dynamically linked executables); and a delay in implementing bind, 4.3BSD system calls and libraries. The absence of memory-mapped file support was regarded as a particular deficiency with Ultrix in comparison to its competitors in the early 1990s.
The last major release of Ultrix was version 4.5 in 1995, which supported all previously supported DECstations and VAXen. There were some subsequent Y2K patches.
The following shells were provided with Ultrix: ULTRIX Worksystem Software, Version 4.2 Software Product Description
BSD
V7m
First release of Ultrix
Later releases of Ultrix
Last release
Application software
See also
Further reading
External links
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